How to generate 4x4 lower triangular matrix?

I want to generate the lower triangular matrix A1 using a for loop instead of using for example 'B(2) - B(1)' for a22 and so on in the matrix.

MATLAB
B = [17.000; 26.000; 29.000; 33.000]; 
A1 = [1 0 0 0; 1 T(2)-T(1) 0 0; 1 T(3)-T(1) (T(3)-T(1))*(T(3)-T(2)) 0; 
  1 T(4)-T(1) (T(4)-T(1))*(T(4)-T(2)) (T(4)-T(1))*(T(4)-T(2))*(T(4)-T(3))]; %Lower Triangular Matrix
end

Answer 1

[Andrei Bobrov]

a = tril(T(:) - T(:)');
A1 =  cumprod([ones(numel(T),1),a(:,1:end-1)],2);